Time schedule and practical arrangments for making a 5’ public domain grid ready by 2001

Other business

1.

The chairman (R. Forsberg) gave a brief presentation of background of ArcGP, and welcomed participants in meeting, including several participants interested primarily in Antarctica gravity field. Group members were thanked for the effort already done.

G. Demianov, Tsniigaik/Russia, talked about Russian land coverage, 10’ grid data to be made available in cooperation with northern hemisphere geoid project. 30’ data compilation used for GAO global earth models.

H.-W. Schenke, AWI/Germany: Presented on behalf of International Arctic Bathymetric Project (IOC/IHO) status of compilations of depth data. Contribution from US submarine surveys 1958-1983 just released. A preliminary model to be finished fall 99. SCICEX submarine data not included yet. Martin Jakobssen, Sweden, did much of practical compilation. Final chart to be published Oct. 2000.

Rene Forsberg, KMS/Denmark mentioned details of some ongoing activities contributed, a.o. AWI surveys in Arctic, which have been contributed to ArcGP. NGA representative showed coverage of current ArcGP sources contributed.

Discussions were made about eventual Russian gravity data release. Russian data made available in some form would be crucial for the project. Some data have allready been contributed, and Russian delegates were optimistic about future declassifications of mean anomaly data (not detailed point values). The Russian Academy of Sciences to be contacted formally about release of data.

4.

It was agreed to to make the grid in the form of a 5’ grid from 64N to the pole, with grid center shifted 2.5’ in accordance with Canadian grids (that has advantage of not having multiple values at North Pole). A special extension of grid to 62 N would be made to include Iceland.

Final grid would be a free-air grid at sea-level (at level of surface of topography on land). A Bouguer anomaly grid will be derived from bathymetry project DEM. This would also require use of 5’ ice thickness models over glaciers and ice caps. Geoid would be another derived product.

Agreed time schedule calls for collection of data until end of 2000, then compilation of all available data and release of grids by mid-2001. Details of final data compilation methods to be discussed at next ArcGP working meeting. This meeting to be held in St. Petersburg, Russia, early 2000. (Limited) support for travel available through IAG and possibly IASC.

5.

Some brief discussion of a future similar project in Antarctica were held, in order to support especially need of satellite geodesy (filling "polar gaps"). Antarctica geodesy activities in general allready closely coordinated through SCAR (www.scar-ggi.org.au/Geodesy).